INFO: task hung in wait_on_page_bit_common

[syzbot]

Hello,

syzkaller hit the following crash on
328b4ed93b69a6f2083d52f31a240a09e5de386a
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.

Unfortunately, I don't have any reproducer for this bug yet.


INFO: task syz-executor7:31107 blocked for more than 120 seconds.
Not tainted 4.15.0-rc2+ #209
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor7 D19408 31107 3309 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2799 [inline]
__schedule+0x8eb/0x2060 kernel/sched/core.c:3375
schedule+0xf5/0x430 kernel/sched/core.c:3434
io_schedule+0x1c/0x70 kernel/sched/core.c:5042
wait_on_page_bit_common+0x4b3/0x770 mm/filemap.c:1100
wait_on_page_bit mm/filemap.c:1133 [inline]
wait_on_page_locked include/linux/pagemap.h:530 [inline]
__lock_page_or_retry+0x3fd/0x500 mm/filemap.c:1311
lock_page_or_retry include/linux/pagemap.h:510 [inline]
filemap_fault+0xcdc/0x1c20 mm/filemap.c:2533
__do_fault+0xeb/0x319 mm/memory.c:3196
do_read_fault mm/memory.c:3606 [inline]
do_fault mm/memory.c:3706 [inline]
handle_pte_fault mm/memory.c:3936 [inline]
__handle_mm_fault+0x1e9e/0x3e20 mm/memory.c:4060
handle_mm_fault+0x334/0x8d0 mm/memory.c:4097
faultin_page mm/gup.c:502 [inline]
__get_user_pages+0x50c/0x15f0 mm/gup.c:699
populate_vma_page_range+0x20e/0x2f0 mm/gup.c:1216
__mm_populate+0x23a/0x450 mm/gup.c:1266
mm_populate include/linux/mm.h:2226 [inline]
vm_mmap_pgoff+0x241/0x280 mm/util.c:338
SYSC_mmap_pgoff mm/mmap.c:1533 [inline]
SyS_mmap_pgoff+0x462/0x5f0 mm/mmap.c:1491
SYSC_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:91
entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a39
RSP: 002b:00007fbdad43ac58 EFLAGS: 00000212 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fbdad43b700 RCX: 0000000000452a39
RDX: 0000000000000003 RSI: 0000000000001000 RDI: 0000000020e5b000
RBP: 0000000000000000 R08: 0000000000000015 R09: 0000000000000000
R10: 0000000000002011 R11: 0000000000000212 R12: 0000000000000000
R13: 0000000000a6f7ff R14: 00007fbdad43b9c0 R15: 0000000000000000

Showing all locks held in the system:
2 locks held by khungtaskd/674:
#0: (rcu_read_lock){....}, at: [<00000000319a6af1>]
check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
#0: (rcu_read_lock){....}, at: [<00000000319a6af1>] watchdog+0x1c5/0xd60
kernel/hung_task.c:249
#1: (tasklist_lock){.?.?}, at: [<00000000a9e72599>]
debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4554
2 locks held by login/3056:
#0: (&tty->ldisc_sem){++++}, at: [<00000000824f8dbe>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&tty->atomic_write_lock){+.+.}, at: [<00000000a7570bad>]
tty_write_lock+0x21/0x60 drivers/tty/tty_io.c:875
2 locks held by getty/3057:
#0: (&tty->ldisc_sem){++++}, at: [<00000000824f8dbe>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000005dd73ff5>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
2 locks held by getty/3058:
#0: (&tty->ldisc_sem){++++}, at: [<00000000824f8dbe>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000005dd73ff5>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
2 locks held by getty/3059:
#0: (&tty->ldisc_sem){++++}, at: [<00000000824f8dbe>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000005dd73ff5>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
2 locks held by getty/3060:
#0: (&tty->ldisc_sem){++++}, at: [<00000000824f8dbe>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000005dd73ff5>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
2 locks held by getty/3061:
#0: (&tty->ldisc_sem){++++}, at: [<00000000824f8dbe>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000005dd73ff5>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
2 locks held by getty/3062:
#0: (&tty->ldisc_sem){++++}, at: [<00000000824f8dbe>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000005dd73ff5>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 674 Comm: khungtaskd Not tainted 4.15.0-rc2+ #209
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:53
nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
check_hung_task kernel/hung_task.c:132 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
watchdog+0x90c/0xd60 kernel/hung_task.c:249
kthread+0x37a/0x440 kernel/kthread.c:238
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:441
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10
arch/x86/include/asm/irqflags.h:54


---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
Direct all questions to syzk...@googlegroups.com.
Please credit me with: Reported-by: syzbot <syzk...@googlegroups.com>

syzbot will keep track of this bug report.
Once a fix for this bug is committed, please reply to this email with:
#syz fix: exact-commit-title
To mark this as a duplicate of another syzbot report, please reply with:
#syz dup: exact-subject-of-another-report
If it's a one-off invalid bug report, please reply with:
#syz invalid
Note: if the crash happens again, it will cause creation of a new bug
report.
Note: all commands must start from beginning of the line in the email body.

[Dmitry Vyukov]

On Wed, Dec 6, 2017 at 1:41 PM, syzbot
<bot+ef061880e2ff14267d...@syzkaller.appspotmail.com>
wrote:

+loop maintainers

#syz dup: INFO: task hung in lo_ioctl

> ---
> This bug is generated by a dumb bot. It may contain errors.
> See https://goo.gl/tpsmEJ for details.
> Direct all questions to syzk...@googlegroups.com.
> Please credit me with: Reported-by: syzbot <syzk...@googlegroups.com>
>
> syzbot will keep track of this bug report.
> Once a fix for this bug is committed, please reply to this email with:
> #syz fix: exact-commit-title
> To mark this as a duplicate of another syzbot report, please reply with:
> #syz dup: exact-subject-of-another-report
> If it's a one-off invalid bug report, please reply with:
> #syz invalid
> Note: if the crash happens again, it will cause creation of a new bug
> report.
> Note: all commands must start from beginning of the line in the email body.
>

> --
> You received this message because you are subscribed to the Google Groups
> "syzkaller-bugs" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to syzkaller-bug...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/syzkaller-bugs/001a113ece8c935efd055fab4367%40google.com.
> For more options, visit https://groups.google.com/d/optout.